Death" by Megadeth (which would later appear in their album Thirteen, released the following year) and written by their front-man Dave Mustaine specifically for the conclusion of the game, and contains portions that he believed were "the most difficult parts" he has written in his life. When the player has completed the battle with the Beast, they have the opportunity to return to the previous venues, now with all eight powers active simultaneously, and attempt to achieve 40-star performances for each song in the game, as well as a comparatively difficult set of songs with the Demigod himself. Video game journalists have noted thematic similarities between the story details of Warriors of Rock and Brütal Legend, an action video game with a world based on heavy metal, developed by Tim Schafer and Double Fine Productions which Activision, at one point, would have published but later dropped the rights. Project lead Brian Bright commented that their inspiration for the game's story was the covers of metal albums, the same material that led to the world of Brütal Legend. In the game's Quickplay+ mode, players can play any song on-disc or from their downloadable content library. Each song has 13 different achievements to be completed. Twelve are similar to the Challenges introduced in Guitar Hero 5, such as getting a high score, maintain a long note streak, or accumulating an amount of Star Power, and each has 3 levels (gold, platinum, and diamond) that translate to 1 to 3 additional stars once reached. If the player has unlocked the Warrior character powers in the Quest mode, they can enable these powers to try to get up to a maximum of 20 stars (21 for successfully completing the song without missing a note or hitting notes that aren't there) on each song for the thirteenth challenge. As the player earns stars in this mode, they will advance in rank and gain additional unlockable features such as alternate outfits or guitars and additional venue selections. Party mode introduced in Guitar Hero 5 is also available, where the game will automatically play songs like a jukebox, and allow for players to drop-in or drop-out at any time. The competitive modes introduced in Guitar Hero 5 are also carried over into Guitar Hero: Warriors of Rock, and are expanded to include band-vs-band variants. The Wii version improves the "Roadie" game version introduced in Guitar Hero 5.